Russian gangsters and other ne'er-do-wells of the 90s still carry old grievances and will continue murdering each other until they are all gone. Since Britain provided the richest of them with a playground, it is not shocking that they are continuing with their modus operandi on a smaller scale there.

As for Skripal, he allegedly blew the cover of 300 Russian agents. That is a lot of people with a personal motive. Perhaps an investigation is in order before Britain and Russia tear their relationship apart over this.